1. Field of the Invention
This invention relates generally to ports for injecting fluids into an intravenous (IV) line, and more specifically to injection manifolds including multiple injection ports.
2. Discussion of the Prior Art
Patients are commonly injected with IV solutions which are initially provided in a bottle or bag and dripped into the vein of the patient through an IV line. Typically an injection port is provided along the line and adapted to function with a syringe to permit an injectate to be added to the IV solution. If a large quantity of injectate, or multiple injectates, are to be added to the IV solution, multiple ports may be required. In such a case, an injection manifold can be disposed in the IV line to provide multiple injection ports.
A check valve is also commonly included in the IV line where it is disposed upstream from the injection manifold. It is the purpose of the check valve to permit fluid flow only in the direction of the patient. This ensures that the injectate flows downstream toward the patient, not upstream toward the IV reservoir.
The prior art is deficient in that it does not adequately provide for check valves at locations than upstream of the ports. Doing so has its advantages in certain applications in which the prior art falls short.
In the past, IV manifolds have been provided with an elongate and generally flat configuration in order to facilitate use of the multiple injection ports. The flow channel through the manifold has also had this elongate wide configuration, and consequently, has been susceptible to the formation of air pockets, and to generally uneven flow characteristics. In the vicinity of the injection ports, the manifolds of the past have also developed dead spaces where the injectate has tended to collect rather than mix with the IV solution. Other IV manifolds have been provided with a round tube defining the flow channel. Injection ports have been connected to this tube at a “T” junction. In this case, the flow channel has remained separate and the problems with dead spaces in the ports have been significant.
Injection ports of the past have generally included only valves with a single valve seal. These seals have not been capable of withstanding high pressure such as those sometimes associated with an injection into an adjacent port. The resulting high back pressure has sometimes caused the valve element to deform and lodge in the lumen of the port, rendering the port inoperative.
In the past, the ports associated with injection manifold have not been provided with characteristics permitting the aspiration of fluids from the flow channel. This is sometimes desirable in order to remove air from the manifold or withdraw a blood sample. In these cases, a separate aspiration port has been required in addition to the injection manifold.
Even the three valve seat system provided by the embodiment having an apertured valve element of the instant invention has some drawbacks for certain applications. For example, this embodiment requires relatively high pressure for both aspiration and injection.
Some injection ports have been provided with operative cages which mechanically open the valves. In this case a syringe having a male Luer fitting is relied on to push the cage against the valve element in order to open the valve. Due to wide tolerance variations in the plastic parts associated with the syringes, the male Luer fittings can sometimes extend into the injection port a distance greater than that required to open the valve. In many of these cases, damage to the injection port has resulted.
Although the cage and valve element embodiment of the instant invention provides a means for permitting unimpeded aspiration, and although the cage of the instant invention provides for inserting a variety of male Luers without damaging the port or manifold, the cage adds a separate piece and increases the complexity of the overall device. With the cage embodiment, changes are also required in the port itself to accommodate the cage. For example, a large portion of the second seat must be removed in order to provide room for the cage.